Process for the metathetic degradation of nitrile rubbers

a technology of nitrile rubber and metathesis catalyst, which is applied in the field of metathetic degradation of nitrile rubber, can solve the problems of inability to reduce the molar mass of the nbr feedstock to be used for hydrogenation, the processingability of hnbr is greatly restricted, and the molar mass of the nbr feedstock can not be reduced, so as to achieve the effect of increasing the activity of metathesis catalyst in the degradation of nitril

Inactive Publication Date: 2008-03-27
ARLANXEO DEUT GMBH
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Benefits of technology

[0021] It has now been found that the activity of metathesis catalysts in the degradation of nitrile rubbers can be increased by using them in combination with a phosphan

Problems solved by technology

The processability of HNBR is greatly restricted by the relatively high Mooney viscosity.
However, this thermomechanical degradation has the disadvantage that functional groups such as hydroxyl, keto, carboxylic acid and ester groups are incorporated into the molecule by partial oxidation and, in addition, the microstructure of the polymer is substantially altered.
The preparation of HNBR having low molar masses corresponding to a Mooney viscosity (ML 1+4 at 100° C.) in the range below 55 or a number average molecular weight of about Mn<200 000 g/mol was not possible by means of established

Method used

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  • Process for the metathetic degradation of nitrile rubbers
  • Process for the metathetic degradation of nitrile rubbers
  • Process for the metathetic degradation of nitrile rubbers

Examples

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examples

[0234] The following examples were carried out using the following catalysts:

“Grubbs II Catalyst”:

[0235] The Grubbs II catalyst was procured from Materia (Pasadena / Calif.).

“Buchmeiser Nuyken Catalyst”:

[0236] The Buchmeiser-Nuyken catalyst (molecular weight: 781.75 g / mol) was prepared by the synthesis published in Adv. Synth. Catal. 2003, 345, 996.

[0237] As phosphane additives, use was made of tricyclohexylphosphane (molecular weight=280.23 g / mol, referred to as PCy3 for short) and triphenylphosphane (molecular weight: 262.09; PPh3 for short); tricyclohexylphosphane and triphenylphosphane were procured from Aldrich.

[0238] The metathesis reactions were carried out using the nitrile rubber Perbunane NT 3435 from Lanxess Deutschland GmbH as substrate.

[0239] This nitrile rubber had the following characteristic properties:

Acrylonitrile content:35%by weightMooney value (ML 1 + 4 at 100° C.):34Mooney unitsResidual moisture content:1.8%by weightMw:240 000g / molMn:100 000g / molPDI (M...

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Abstract

An improved process for the metathetic degradation of nitrile rubber using catalyst systems comprising the catalyst and also a phosphane or diphosphane is provided.

Description

FIELD OF THE INVENTION [0001] The invention relates to an improved process for the metathetic degradation of nitrile rubber in the presence of a catalyst and of a specific additive. BACKGROUND OF THE INVENTION [0002] The term nitrile rubber, also referred to as “NBR” for short, refers to rubbers which are copolymers or terpolymers of at least one α,β-unsaturated nitrile, at least one conjugated diene and, if desired, further copolymerizable monomers. [0003] Hydrogenated nitrile rubber, also referred to as “HNBR” for short, is produced by hydrogenation of nitrile rubber. Accordingly, the C═C double bonds of the copolymerized diene units are entirely or partly hydrogenated in HNBR. The degree of hydrogenation of the copolymerized diene units is usually in the range from 50 to 100%. [0004] Hydrogenated nitrile rubber is a specialty rubber which has very good heat resistance, excellent resistance to ozone and chemicals and excellent oil resistance. The abovementioned physical and chemic...

Claims

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Application Information

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IPC IPC(8): C08C19/02
CPCC08C19/02C08C19/08C08F8/50C08F8/04C08C2019/09C08C2/04C08C19/24
Inventor OBRECHT, WERNERMULLER, JULIA MARIANUYKEN, OSKARKELLNER, MONIKA
Owner ARLANXEO DEUT GMBH
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